Social Drinking

I went to the doctor this morning and as you know, a standard question is "Do you drink alcohol? If so, how often?" My typical answer is "socially, on the weekends." But really, what does socially mean? To me, it refers to being out with your friends and drinking - you know, during a gathering of sorts.
HOWEVER, is it still considered "social" drinking when this assemblage results in blackouts by one or more parties involved? I consider myself a social drinker, as I said, but if I'm blacking out every weekend night - clearly, it's more than just social drinking. It's like, um, a problem.